Process to prepare treprostinil, the active ingredient in remodulin®

A pharmaceutical batch of a salt of treprostinil that can be stored as a stable compound at ambient temperature and that is prepared by a method comprising (a) alkylating a benzindene triol, (b) hydrolyzing the product of step (a) to form a solution comprising treprostinil, and (c) contacting the solution comprising treprostinil from step (b) with a base to form a salt of treprostinil, wherein forming the salt of step (c) reduces the amount of one or more impurities resulting from steps (a) and/or (b) in the pharmaceutical batch, said pharmaceutical batch being at least 2.9 grams.